libstdc++-v3/config/io/basic_file_stdio.cc

   1 // Wrapper of C-language FILE struct -*- C++ -*-
   2
   3 // Copyright (C) 2000, 2001, 2002, 2003, 2004 Free Software Foundation, Inc.
   4 //
   5 // This file is part of the GNU ISO C++ Library.  This library is free
   6 // software; you can redistribute it and/or modify it under the
   7 // terms of the GNU General Public License as published by the
   8 // Free Software Foundation; either version 2, or (at your option)
   9 // any later version.
  10
  11 // This library is distributed in the hope that it will be useful,
  12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 // GNU General Public License for more details.
  15
  16 // You should have received a copy of the GNU General Public License along
  17 // with this library; see the file COPYING.  If not, write to the Free
  18 // Software Foundation, 59 Temple Place - Suite 330, Boston, MA 02111-1307,
  19 // USA.
  20
  21 // As a special exception, you may use this file as part of a free software
  22 // library without restriction.  Specifically, if other files instantiate
  23 // templates or use macros or inline functions from this file, or you compile
  24 // this file and link it with other files to produce an executable, this
  25 // file does not by itself cause the resulting executable to be covered by
  26 // the GNU General Public License.  This exception does not however
  27 // invalidate any other reasons why the executable file might be covered by
  28 // the GNU General Public License.
  29
  30 //
  31 // ISO C++ 14882: 27.8  File-based streams
  32 //
  33
  34 #include <bits/basic_file.h>
  35 #include <fcntl.h>
  36 #include <errno.h>
  37
  38 #ifdef _GLIBCXX_HAVE_POLL
  39 #include <poll.h>
  40 #endif
  41
  42 // Pick up ioctl on Solaris 2.8
  43 #ifdef _GLIBCXX_HAVE_UNISTD_H
  44 #include <unistd.h>
  45 #endif
  46
  47 // Pick up FIONREAD on Solaris 2
  48 #ifdef _GLIBCXX_HAVE_SYS_IOCTL_H
  49 #define BSD_COMP
  50 #include <sys/ioctl.h>
  51 #endif
  52
  53 // Pick up FIONREAD on Solaris 2.5.
  54 #ifdef _GLIBCXX_HAVE_SYS_FILIO_H
  55 #include <sys/filio.h>
  56 #endif
  57
  58 #ifdef _GLIBCXX_HAVE_SYS_UIO_H
  59 #include <sys/uio.h>
  60 #endif
  61
  62 #if defined(_GLIBCXX_HAVE_S_ISREG) || defined(_GLIBCXX_HAVE_S_IFREG)
  63 # include <sys/stat.h>
  64 # ifdef _GLIBCXX_HAVE_S_ISREG
  65 #  define _GLIBCXX_ISREG(x) S_ISREG(x)
  66 # else
  67 #  define _GLIBCXX_ISREG(x) (((x) & S_IFMT) == S_IFREG)
  68 # endif
  69 #endif
  70
  71 #include <limits> // For <off_t>::max() and min() and <streamsize>::max()
  72
  73 namespace __gnu_internal
  74 {
  75   // Map ios_base::openmode flags to a string for use in fopen().
  76   // Table of valid combinations as given in [lib.filebuf.members]/2.
  77   static const char*
  78   fopen_mode(std::ios_base::openmode mode)
  79   {
  80     enum
  81       {
  82         in     = std::ios_base::in,
  83         out    = std::ios_base::out,
  84         trunc  = std::ios_base::trunc,
  85         app    = std::ios_base::app,
  86         binary = std::ios_base::binary
  87       };
  88
  89     switch (mode & (in|out|trunc|app|binary))
  90       {
  91       case (   out                 ): return "w";
  92       case (   out      |app       ): return "a";
  93       case (   out|trunc           ): return "w";
  94       case (in                     ): return "r";
  95       case (in|out                 ): return "r+";
  96       case (in|out|trunc           ): return "w+";
  97
  98       case (   out          |binary): return "wb";
  99       case (   out      |app|binary): return "ab";
 100       case (   out|trunc    |binary): return "wb";
 101       case (in              |binary): return "rb";
 102       case (in|out          |binary): return "r+b";
 103       case (in|out|trunc    |binary): return "w+b";
 104
 105       default: return 0; // invalid
 106       }
 107   }
 108
 109   // Wrapper handling partial write.
 110   static std::streamsize
 111   xwrite(int __fd, const char* __s, std::streamsize __n)
 112   {
 113     std::streamsize __nleft = __n;
 114
 115     for (;;)
 116       {
 117         const std::streamsize __ret = write(__fd, __s, __nleft);
 118         if (__ret == -1L && errno == EINTR)
 119           continue;
 120         if (__ret == -1L)
 121           break;
 122
 123         __nleft -= __ret;
 124         if (__nleft == 0)
 125           break;
 126
 127         __s += __ret;
 128       }
 129
 130     return __n - __nleft;
 131   }
 132
 133 #ifdef _GLIBCXX_HAVE_WRITEV
 134   // Wrapper handling partial writev.
 135   static std::streamsize
 136   xwritev(int __fd, const char* __s1, std::streamsize __n1,
 137           const char* __s2, std::streamsize __n2)
 138   {
 139     std::streamsize __nleft = __n1 + __n2;
 140     std::streamsize __n1_left = __n1;
 141
 142     struct iovec __iov[2];
 143     __iov[1].iov_base = const_cast<char*>(__s2);
 144     __iov[1].iov_len = __n2;
 145
 146     for (;;)
 147       {
 148         __iov[0].iov_base = const_cast<char*>(__s1);
 149         __iov[0].iov_len = __n1_left;
 150
 151         const std::streamsize __ret = writev(__fd, __iov, 2);
 152         if (__ret == -1L && errno == EINTR)
 153           continue;
 154         if (__ret == -1L)
 155           break;
 156
 157         __nleft -= __ret;
 158         if (__nleft == 0)
 159           break;
 160
 161         const std::streamsize __off = __ret - __n1_left;
 162         if (__off >= 0)
 163           {
 164             __nleft -= xwrite(__fd, __s2 + __off, __n2 - __off);
 165             break;
 166           }
 167
 168         __s1 += __ret;
 169         __n1_left -= __ret;
 170       }
 171
 172     return __n1 + __n2 - __nleft;
 173   }
 174 #endif
 175 } // namespace __gnu_internal
 176
 177 namespace std
 178 {
 179   // Definitions for __basic_file<char>.
 180   __basic_file<char>::__basic_file(__c_lock* /*__lock*/)
 181   : _M_cfile(NULL), _M_cfile_created(false) { }
 182
 183   __basic_file<char>::~__basic_file()
 184   { this->close(); }
 185
 186   __basic_file<char>*
 187   __basic_file<char>::sys_open(__c_file* __file, ios_base::openmode)
 188   {
 189     __basic_file* __ret = NULL;
 190     if (!this->is_open() && __file)
 191       {
 192         int __err;
 193         errno = 0;
 194         do
 195           __err = this->sync();
 196         while (__err && errno == EINTR);
 197         if (!__err)
 198           {
 199             _M_cfile = __file;
 200             _M_cfile_created = false;
 201             __ret = this;
 202           }
 203       }
 204     return __ret;
 205   }
 206
 207   __basic_file<char>*
 208   __basic_file<char>::sys_open(int __fd, ios_base::openmode __mode)
 209   {
 210     __basic_file* __ret = NULL;
 211     const char* __c_mode = __gnu_internal::fopen_mode(__mode);
 212     if (__c_mode && !this->is_open() && (_M_cfile = fdopen(__fd, __c_mode)))
 213       {
 214         char* __buf = NULL;
 215         _M_cfile_created = true;
 216         if (__fd == 0)
 217           setvbuf(_M_cfile, __buf, _IONBF, 0);
 218         __ret = this;
 219       }
 220     return __ret;
 221   }
 222
 223   __basic_file<char>*
 224   __basic_file<char>::open(const char* __name, ios_base::openmode __mode,
 225                            int /*__prot*/)
 226   {
 227     __basic_file* __ret = NULL;
 228     const char* __c_mode = __gnu_internal::fopen_mode(__mode);
 229     if (__c_mode && !this->is_open())
 230       {
 231 #ifdef _GLIBCXX_USE_LFS
 232         if ((_M_cfile = fopen64(__name, __c_mode)))
 233 #else
 234         if ((_M_cfile = fopen(__name, __c_mode)))
 235 #endif
 236           {
 237             _M_cfile_created = true;
 238             __ret = this;
 239           }
 240       }
 241     return __ret;
 242   }
 243
 244   bool
 245   __basic_file<char>::is_open() const
 246   { return _M_cfile != 0; }
 247
 248   int
 249   __basic_file<char>::fd()
 250   { return fileno(_M_cfile); }
 251
 252   __c_file*
 253   __basic_file<char>::file()
 254   { return _M_cfile; }
 255
 256   __basic_file<char>*
 257   __basic_file<char>::close()
 258   {
 259     __basic_file* __ret = static_cast<__basic_file*>(NULL);
 260     if (this->is_open())
 261       {
 262         int __err = 0;
 263         if (_M_cfile_created)
 264           {
 265             // In general, no need to zero errno in advance if checking
 266             // for error first. However, C89/C99 (at variance with IEEE
 267             // 1003.1, f.i.) do not mandate that fclose must set errno
 268             // upon error.
 269             errno = 0;
 270             do
 271               __err = fclose(_M_cfile);
 272             while (__err && errno == EINTR);
 273           }
 274         _M_cfile = 0;
 275         if (!__err)
 276           __ret = this;
 277       }
 278     return __ret;
 279   }
 280
 281   streamsize
 282   __basic_file<char>::xsgetn(char* __s, streamsize __n)
 283   {
 284     streamsize __ret;
 285     do
 286       __ret = read(this->fd(), __s, __n);
 287     while (__ret == -1L && errno == EINTR);
 288     return __ret;
 289   }
 290
 291   streamsize
 292   __basic_file<char>::xsputn(const char* __s, streamsize __n)
 293   { return __gnu_internal::xwrite(this->fd(), __s, __n); }
 294
 295   streamsize
 296   __basic_file<char>::xsputn_2(const char* __s1, streamsize __n1,
 297                                const char* __s2, streamsize __n2)
 298   {
 299     streamsize __ret = 0;
 300 #ifdef _GLIBCXX_HAVE_WRITEV
 301     __ret = __gnu_internal::xwritev(this->fd(), __s1, __n1, __s2, __n2);
 302 #else
 303     if (__n1)
 304       __ret = __gnu_internal::xwrite(this->fd(), __s1, __n1);
 305
 306     if (__ret == __n1)
 307       __ret += __gnu_internal::xwrite(this->fd(), __s2, __n2);
 308 #endif
 309     return __ret;
 310   }
 311
 312   streamoff
 313   __basic_file<char>::seekoff(streamoff __off, ios_base::seekdir __way)
 314   {
 315 #ifdef _GLIBCXX_USE_LFS
 316     return lseek64(this->fd(), __off, __way);
 317 #else
 318     if (__off > numeric_limits<off_t>::max()
 319         || __off < numeric_limits<off_t>::min())
 320       return -1L;
 321     return lseek(this->fd(), __off, __way);
 322 #endif
 323   }
 324
 325   int
 326   __basic_file<char>::sync()
 327   { return fflush(_M_cfile); }
 328
 329   streamsize
 330   __basic_file<char>::showmanyc()
 331   {
 332 #ifdef FIONREAD
 333     // Pipes and sockets.
 334 #ifdef _GLIBCXX_FIONREAD_TAKES_OFF_T
 335     off_t __num = 0;
 336 #else
 337     int __num = 0;
 338 #endif
 339     int __r = ioctl(this->fd(), FIONREAD, &__num);
 340     if (!__r && __num >= 0)
 341       return __num;
 342 #endif
 343
 344 #ifdef _GLIBCXX_HAVE_POLL
 345     // Cheap test.
 346     struct pollfd __pfd[1];
 347     __pfd[0].fd = this->fd();
 348     __pfd[0].events = POLLIN;
 349     if (poll(__pfd, 1, 0) <= 0)
 350       return 0;
 351 #endif
 352
 353 #if defined(_GLIBCXX_HAVE_S_ISREG) || defined(_GLIBCXX_HAVE_S_IFREG)
 354     // Regular files.
 355 #ifdef _GLIBCXX_USE_LFS
 356     struct stat64 __buffer;
 357     const int __err = fstat64(this->fd(), &__buffer);
 358     if (!__err && _GLIBCXX_ISREG(__buffer.st_mode))
 359       {
 360         const streamoff __off = __buffer.st_size - lseek64(this->fd(), 0,
 361                                                            ios_base::cur);
 362         return std::min(__off, streamoff(numeric_limits<streamsize>::max()));
 363       }
 364 #else
 365     struct stat __buffer;
 366     const int __err = fstat(this->fd(), &__buffer);
 367     if (!__err && _GLIBCXX_ISREG(__buffer.st_mode))
 368       return __buffer.st_size - lseek(this->fd(), 0, ios_base::cur);
 369 #endif
 370 #endif
 371     return 0;
 372   }
 373 }  // namespace std